Filament attachment for electric glow-lamps.



N0. 768,173. PATENTBD AUG. 23, 1904 T RFANTA. v

FILAMENT ATTACHMENT FOR BLBGTRIG GLOW LAMPS.

- APPLICATION TILED NOV. 2, 1903. NO 1101131..

* ff 1 UNITED STATES by the glass bulb, wherebyagreat Patented. August23, 1904;

FERDINAND FANTA, OF LONDON, ENGLAND.

FILANIENT ATTACHMENT FOR ELECTRIC GLOW-LAMPS.

SPECIFICATION forming part of Letters Patent No. 768,173, dated August23, 1904:.

Applica ion fiie November 2. 1903. Serial No. 179,584. (No model.)

To all whom it may concern:

Be it known that I, FERDINAND FANTA, a subject of the King of GreatBritain and-Ireland, residing at London, England, have invented acertain new and useful Improvement in andRelating to FilamentAttachments for Electric Glow-Lamps, of which the following is aspecification.

This invention relates to novel means for attaching a carbon filamentwith a predetermined length and resistance to the platinum conductors ofincandescent electric lamps held saving in labor is obtained and thefilament may be re newed in a lamp any number of times.

. I am aware that new filaments have been introduced into the bulbs ofold lamps and that I the said filaments have been joined to the platinumconductors within the bulbs of such lamps, but the methods and deviceshitherto used for this purpose have been such that great disadvantagesand difiiculties have been experienced in producing a satisfactoryresult. For example, the filament when flashed is very much more brittleand fragile than when unflashed. Hence the risk of damage during theaction of inserting the new flashed filament into an old bulb through asmall hole made therein is very great, and, further, it is verydifficult to insure the jointing of the ends of the filament to theplatinum conductors under these conditions in-such a manner that apredetermined length of filament with a given resistance is establishedfrom one point to the other point of connection. This would result in aconsiderable want of uniformity and standardability in the lamps sotreated. Again, when a metallic sleeve only is used on the filament thereplacing of the filament can only be effected once, as the said sleevemust be firmly gripped onto the platinum ends in the bulb and cannotafterward be withdrawn therefrom. This invention entirelyovercomes thesedisadvantages and enables new lamps to be manufactured with ease andeconomy hitherto unattainable and old lamps to be readily renewed withnew filaments in a certain and reliable manner as to the uniformity ofresult.

Figure 1 is a general view of theglow-lamp I with filament fixedtherein.

Fig. 2 is an en I larged section through the joints, and Fig. 3 showsdetached details of the tubes.

To carry this invention into effect, a predetermined length ofpreferably unflashed filament f is taken, and to each end thereof ametallic tube or jointing device a of sufficient diameter to have itsexterior face accurately turned or gaged is attached by any known orcombination of known means, these jointing devices insuring that adefinite length of filaiment is disposed between the metallic termienals as such jointing devices are affixed to the filament when easilyhandled outside the lamp. The jointing devices are in the form of a com-5 pressible tube or socket, gripped onto the end 7 of the filament andsecured there by carbon paste 6 to insure continuity of electricalconduction. They are of such an external diameter as to allow of theirbeingaccurately 7 .the bulbs have the platinum conductors securedtherein with their free'endsprojecting into the bulb without filamentattached thereto, contrary to existing practice, and instead of thefilament a small metallic sleeve 0, having an accurately-bored interior,is fixed onto such platinum ends d, and this can be done either beforethe platinum is annealed into the glass bulb or it may be fixed at alater period in the 5 manner hereinafter described. In the case of oldlamps a hole is made in the bulb, the old filament is abstracted,metallic terminals in the bulb are cleaned by means of a small tool,such as an adjustable chuck with cleaning de- 9 vices carried thereby,mounted upon a tube or handle and adapted so that the chuck can beinserted into the bulb and can be adjusted to press upon the saidconductors and then revolved or reciprocated in order to clean theplatinum wires. The platinum ends are then cut to a uniform length by acutting-tool provided with a gage, and a small sleeve .0, having anaccurately-bored interior approximately twice as long as the remnantparts of the platinum wires, is placed on each. These two sleeves arefirst perforated with small transverse pin-holes 9 about the center inorder to place the inside of these sleeves in free communication withthe vacuum. The sleeves are then pinched and firmly secured onto theplatinum ends by a specially constructed compressing-tool in such a wayas to permanently grip them onto the same, while leaving the upper partof the sleeve open for the reception of the metallic terminals a of thenew filaments. The filament with its end furnished with metallicterminals a is now introduced into the bulb, and the terminals a areengaged into the sleeves upon the platinum conductors, and the jointbetween the two metallic parts is made in any known manner, but in sucha manner that electrical continuity is insured and that the metallicterminal of the filament may be afterward withdrawn from the sockets onthe platinum conductors. This may be conveniently done by using a carbonpaste a. When an unflashed filament has been used, the lamp can then beplaced on the photometer and flashed in any convenient manner, or if theflashed filaments are used the lamp can then be exhausted and sealed upin the usual manner.

It may be pointed out that in manufacturing new lamps in this way agreat economy 'in labor obtains, owing to the much greater facility insealing platinum conductors with out any filament attached thereto intothe glass of the bulb as compared with the usual method in which thevery brittle flashed filament is attached to the platinum conductorsbefore sealing the latter into the glass bulb. The character of laborrequired for this invention is therefor not of such a delicate and highclass as is necessary at present, and is therefore much cheaper. Itwill, moreover, be selfevident that while lamps manufactured inaccordance with this invention may have their filaments replaced timeafter time old lamps of any make that have been allowed to burn out canbe provided with the sleeve attachment and thereafter be repeatedlyprovided with new filaments at a trifling cost.

Having now described my invention, what I claim, and desire to secure byLetters Patent, is

1. In combination in an incandescent electric lamp, a filament, tubularmetallic tips carried by the ends of the filament, metallic tubessecured to the platinum leads protruding from the lamp-socket, saidtubes extending beyond the platinum leads and having the metallic tubeson the filament ends accurately filling in and securedthereto,substantiall y as described.

2. In combination in an incandescent electric lamp, a filament, tubularmetallic tips carried by the ends of the filament, metallic tubessecured to the platinum leads protruding from the lamp socket, andtransverse openings through the said tubes situated between the ends ofthe platinum leads and the tubular metallic tips of the filaments, thesaid tubes extending beyond the platinum leads and leaving the tubulartips of the filament accurately fitting in the extended parts thereof.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

FERDINAND FANTA.

Witnesses:

RICHARD A. HOFFMANN, CHARLES CARTER.

